| Background:(1)Current status and harm of myopia in children and adolescents.The eye is the most important sensory organ of the human body.With the development of modern society,the burden of eye use is increasing.Myopia has become widespread worldwide,and the prevalence of myopia in children and adolescents has increased more rapidly.In 2018,research conducted by eight departments including the National Health Commission and the Ministry of Education showed that the overall prevalence of myopia among children and adolescents in primary and secondary schools in my country has reached 53.6%.Myopia has a great impact on national security,social economy and personal development.(2)The state and society attach great importance to the high incidence of myopia in children and adolescents.The country and the whole society attach great importance to the high incidence of myopia in children and adolescents.Eight departments including the National Health and Construction Commission and the Ministry of Education jointly issued the "Comprehensive Prevention and Control of Myopia in Children and Adolescents Implementation Plan".The prevention and control of myopia in children and adolescents has become a national strategy.(3)The influence of physical activities,outdoor activities,and near work on children and adolescents myopia.Studies have shown that physical activity,outdoor activities,near work and other environmental factors are the main factors affecting the high incidence of myopia in children and adolescents.Literature review and current research deficiencies: domestic and foreign studies focus on the impact of total time of physical activity on myopia,while ignoring the difference in the impact of high,middle and low levels of physical activity on myopia,and whether the impact of physical activity on myopia is affected by outdoor activities The impact is still controversial;the current literature mostly explores all close-range work as a unified variable or focuses on the impact of reading and writing on myopia,while using computers,mobile phones,playing handheld game consoles,playing musical instruments and other close-range work There are few studies on the impact of myopia;finally,the current studies are mostly cross-sectional surveys,and there are few studies on the factors affecting the progression of myopia in children and adolescents.Purposes:(1)To analyze the impact of physical activity of different intensities(low,medium,and high intensity physical activity)on the prevalence of myopia in children and adolescents,and whether the impact of physical activity on the prevalence of myopia in children and adolescents is interfered by outdoor activities;(2)Analyze the impact of various short-distance work(reading and writing,using computers,using mobile phones,playing handheld games,playing musical instruments,etc.)on the prevalence of myopia in children and adolescents;(3)Through a one-year cohort study,analyze physical activity,outdoor The influence of activities and near work on the progress of myopia in children and adolescents who have been nearsighted.Significance:(1)Theoretical significance: To enrich the connotation of myopia research in my country,to provide a scientific basis for improving the public healthservice system for children and adolescents in my country,to promote the physical and mental health of children and adolescents,and to formulate recommended standards for the physical activity of children and adolescents in my country,and to further adopt relevant measures.Measures to prevent and control myopia in children and adolescents provide a theoretical basis.(2)Practical significance: Parents can adjust students’ physical activity,outdoor time level and near work mode according to the research results to help children grow up healthily.Participants: This study was conducted from October to November in 2019.The subjects were primary school students and junior middle school students in Shanghai.Stratified sampling method was used to select the survey objects.Three districts were selected in the central urban area and the suburb respectively.One public primary school and one public junior middle school were randomly selected from each district.A total of six primary schools and six junior middle schools were selected.In grade3-5 of primary school and grade 6-9 of junior middle school,two classes were randomly selected as the survey and test objects,and a total of 2015 students from 72 classes were selected.A one-year follow-up study was conducted among 795 children and adolescents who participated in the baseline cross-sectional study.Methods:(1)Literature data method: Checked the data and data related to physical activities,outdoor activities,near work,children and adolescents,myopia-related books,policy documents,journals,etc.for two years.(2)Questionnaire survey method: Use the International Physical Activity Questionnaire-short paper to measure the physical activity level of children and adolescents,use the outdoor time Questionnaire to measure the outdoor time level of children and adolescents,and use the near work Questionnaire to measure the level of near work.(3)Measurement method: use standard logarithmic visual acuity chart to measure children and adolescents’ vision.(4)Mathematical statistics: use SPSS24.0 software for statistical analysis of data.Results:(1)The prevalence rate of myopia among primary and middle school students in Shanghai from grades 3 to 9 is 61.7%,and there are significant gender differences and school-level differences.The prevalence of myopia in girls is higher than that in boys,and the prevalence of myopia in junior high school students is higher.Yu elementary school students.(2)The daily low,medium and high physical activity duration and outdoor time duration of Shanghai children and adolescents in grades 3-9 are 55.0 ± 49.1min,35.2 ± 35.3min,40.1 ± 35.6min,75.3 ± 58.2min,respectively.The duration of high-intensity physical activity(OR=0.874,95%CI:0.776~0.984,P=0.000)and the duration of outdoor activities(OR=0.750,95%CI:0.642~0.875,P=0.004)are related to the prevalence of myopia in children and adolescents.The significant negative correlation indicates that high-intensity physical activity and outdoor activities have protective effects on children and adolescents’ eyesight,and the protective effect of high-intensity physical activity on children’s and adolescents’ eyesight is affected by outdoor activities.(3)The total daily close-up time,reading and writing time,computer time,mobile phone time,handheld game console time,and musical instrument time for children and adolescents in grades 3-9in Shanghai are 388.0 ± 183.2min and 281.4 ± 136.4,respectively min,17.9 ±36.9min,48.9±55.4min,8.5±30.3min.There are significant differences in the length of reading and writing,the length of computer watching,the length of playing handheld game consoles,and the length of playing musical instruments.The length of playing a musical instrument is significantly shorter than that of girls,and the length of watching computers and playing handheld game consoles is significantly longer than that of girls.The total hours of near work,reading and writing,computer hours,and mobile phone hours of primary school students are significantly less than those of junior high school students.The total time of short-distance work(OR=1.039,95%CI:1.007~1.071,P=0.015),the length of reading and writing(OR=1.086,95%CI:1.039~1.135,P=0.000)and the length of looking at the phone(OR=1.150,95%CI:1.021~1.294,P=0.021)is positively correlated with myopia in children and adolescents.The length of musical instrument playing has a substitution effect on the length of reading and writing,but is negatively correlated with the risk of myopia(OR=0.711,95%CI: 0.575~0.880,P=0.002).The positive correlation between the length of time spent at the computer and the risk of myopia only exists in elementary school students(OR=1.473,95%CI: 1.062~2.044,P=0.020).It shows that reading and writing,looking at mobile phones,and looking at computers are risk factors for children and adolescents’ vision.(4)The progress of myopia in junior high school students is significantly faster than that of elementary school students.Among the various factors that affect the progress of myopia in children and adolescents,only the duration of outdoor activities is negatively correlated with the progress of myopia in children and adolescents(B=-0.032,P=0.032).High,medium,and low-intensity physical activity and reading and writing time,computer time,mobile phone time,handheld game console time,and musical instrument time have not been found to be significantly correlated with the progression of myopia in children and adolescents.This shows that only outdoors Duration is a key factor affecting the progression of myopia in children and adolescents.In summary,the current prevalence of myopia among children and adolescents in grades 3 to 9 in Shanghai is 61.7%,and the prevalence of myopia is relatively high.High-intensity physical activities and outdoor activities have a protective effect on the eyesight of children and adolescents,and the protective effect of high-intensity physical activities on the eyesight of children and adolescents is affected by outdoor activities.Reading and writing,looking at mobile phones and computers are risk factors for children and adolescents’ vision.Among the various factors that affect the progression of myopia in children and adolescents,only the length of outdoor activities is the key factor that affects the progression of myopia in children and adolescents.Therefore,society,schools,and parents should understand the dangers of myopia,pay attention to children ’s myopia,arrange teaching courses reasonably,control the length of near work,and urge children and adolescents to engage in more physical activities,and pay attention to their intensity,and perform high-intensity outdoors as much as possible.Physical activity. |
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